Spacer for depolarizing bobbins



May 18 1926. 1,585,077

A. J. BRIGGS SPACER FOR DEPOLARIZING BOBBINS Filed April 14, 1924 e wml' @ttor ne 121.4.

Patented May 18, 1926.

UNITED STATES .PATENT oFFlc/E.

.ARTHUR J. BRIGGS, OF SYRACUSE, NEW YORK, ASSIGNOR '10 NATIONAL CARBON COMPANY, INC., A. CORPORATION F NEW YORK. i

SPACER FOR DEPOLARIZING BOBBINS.

Application led April 14, 1924. Serial No. 706,515.

This invention relates primarily to centering and insulating means for dry cell depolarizing bobbins. More particularly, the

I invention comprises an improved insulating spacer adapted to receive the bottom of the bobbin and to hold it positively in central position in the zinc container electrode.

Bobbins have heretofore been provided with various forms of bottom insulating members, such as paraflined paper cups, flexible sheets. having their corners or marginal serrations upturned about the bobbin, and analogous devices. These accomplish more or less satisfactorily the essential resul-t of keeping the bobbin'out of actual contact with the zinc.

But the prior bottom caps and the likedon not generally insure the accurate centeringv of the bobbin. -The inner diameter of 'the zinc container ordinarily exceeds that of the bobbin, plus the thickness of 4its encircling spacing member, by an amount which allows the bobbin considerable freedom of movement. The position of the bobbin is in such lcase largely determined by the way in which it is inserted. In quantity production 1t is obviously impractical to use the care. necessary to insert the bobbin 'centrally in every cell. A large part of the output, therefore, will have the` bobbin decidedly off center, either initially or by subsequent shifting of the bobbin with respect to the container. Further, prior spacing devices usually obstruct electrolytic action upon a portion of the "zinc surface nd cause irregular corrosion of other porliions. l

It is highly desirable that the bobbin be accurately centered, as otherwise seriqus d 1sadvantages may arise, such as excessive zmc corrosion on restricted areas, and danger of short circuiting. In accordance -with the present invention, there is provided an 1nsulating spacer whlch posltively holds and centers ythe bobbin, without attendant disadvantages Reference is to be made to the accompanying drawing,in which Fig. 1 is a perspective view of a dry cell including the improved spacer, the zinc cup being partly broken away;

Fig. 2 is a vertical section through the cell of Fig. 1;

Fig. 3 is a plan view of the s acer as it appears before insertion in a ce1 and v'plied in other forms of spacer.

Figl: is a view similar to Fig. 3, showing a modified form of spacer.

' Referring to Figs. 1 to 3, numeralV l d'onotes a mix bobbin inserted in a zinc cup 2 'and adapted to be embedded in electrolyte paste, not shown. The spacer 3, in which the present inventlon resldes, comprises in a preferred form a sheet 4 of suitable in-` sulating material having tangs 5. The sheet has approximatelythe outline and dimensions of a hexagon inscribed in a circle having a diameter approaching the inner diameter of the cup. The rounded corners 6 on the sheet therefore lie closely adjacent to the wall of the cup and lateral movement is prevented. Further, the tangs when upturned define a seat adapted to receive snu ly a bobbin of average size.

The bobbin isjaccordmgly retained in the desired central The new spacer, usedin cell manufacture on a commercial scale, has very materially reduced the percentage of defectively assembled cells. An important feature of the invention is the attainment o'f this result without substantially disturbing the'electrolytic action. The active zinc surface is engaged byl the apex only of each tang 5 and there are no obstructing areas between bobbin and zinc of sufiicient extent to cause objectionably localized action.

It will be clearrthat the spacer will function though the bobbins be somewhat over size orunder size. In either case the tangs limit the position of the bobbin to a restricted central area and prevent contact withthe zinc.

The principle of the invention may beap- It is essential only that there be two effective marginal portions, one for engaging the cell wall' and the other for engaging the bobbin. For

position, since its seat is positively centered bending. Pulpboard impregnated With parailin is a suitable material for the spacers, but other insulating materials may be used. lVhere it is desired to expose the bottom of the zinc cup to electrolytic action, the spacer may be made of permeable material. The bottom of the cup in such circumstances may be thickened or reinforced, as described in an application of H. W. Heise and E. A. Schumacher, Serial No. 680,249, filed December 12, 1923.

The spacer maybe placed in the bottom of the zinc cup before pouring in the electrolyte and inserting the bobbin, but the preferred method of assembly is as follows: The required amount of paste is poured into the cup, the spacer is pushed into the cup to a point about one-half inch below its brim, and the bobbin is then placed on the spacer and forced to the bottom of the cup. The paste flows upward between the tangs into operative position about the bobbin. Other procedures are also suitable, such as fitting the spacer over t-he bobbin before inserting it. v

The improved spacer is especially adapted for use with dry cell bobbins provided with no surface protecting means. The spacer tends to prevent the bottom of the bobbin from crumbling, which is frequently encountered When unprotected bobbins are used. The spacer is of course advantageous in other connections, including wrapped bobbin assemblies. While primarily intended as a spacing and centering means for small dry cells of the Le Clanche type, the improved spacer may be used with numerous other cells in which similar results are sought.

I claim:

1. A galvanic cell comprising a container, a depolarizing bobbin therein, a spacer comprising a member with marginal portions ying substantially on the circumference of a circle having a diameter approaching the inner diameter of the container, whereby substantial lateral movement of the spacer in the container is prevented, said member having further marginal portions defining a central area approximating that of the base of the 'bobbin and adapted to retain the same in such central area.

2. A galvanic cell comprising a container,

"a depolarizing bobbin therein, a spacer comprising a sheet having corners adapted to engage the side walls of the container, said sheet having tangs upturned between the corners and adapted to receive the bobbin snugly therebetween.

3. A dry cell comprising a zinc cup, a depolarizing bobbin therein, a spacer comprising a sheet having in general the outline ot' a polygon inscribed in a circle of' a diameter approaching ,the inner diameter of the cup, said sheet having #bobbin retaining portions thereon defining a central area approximat ing that of the base of the bobbin and adapted to retain the same in such central area.

4. A dry cell comprising a zinc cup, a depolarizing bobbin therein, a spacer comprising a generally hexagonal sheet of insulatlng material shaped to fit snugly within the cup and having tangs thereon at points between the vertices otl the hexagon delining a. central seat for the bobbin.

5. A dry cell comprising a zinc cup, a dcpolarizing bobbin therein, a spacer comprising a sheet of' insulating material shaped to fit snugly within the cup and having tangs thereon scored along their line of junction with the sheet for lbending upward to engage the base of the bobbin and to center it with respect to the cup.

6. A dry cell comprising a zinc cup, a depolarizing bobbin therein, a spacer comprising substantially rigid portions adapted to engage the side Walls of the cup and to fit snugly therein and flexible portions adapted to bend upwardly about the bobbin and hold it in central position.

t In testimony whereof, I aliix my signaure.

ARTHUR J. BRIGGS. 

